Abrasive product



Feb. 6, 1962 J. E. CAMP ETAL 3,020,139

ABRASIVE PRODUCT Filed April 18, 1960 2 Sheets-Sheet 1 FIGS JOHN F. CRMPFREDERICK 6. SRNDHOLDT GEORGE L. HIJYWOOD INVENTORS WKQJM ATTORNEY JOSEFc. MUELLERJR.

Feb. 6, 1962 J. E. CAMP ETAL 3,

ABRASIVE PRODUCT Filed April 18, 1960 2 Sheets-Sheet 2 JOHN E. C/IHPJMEF C. MUELLER, J R.

FREPERIC K G. SflND/MLDT GE ORGE L. HH YWOOD IN VEN TORS BYMY/M ATTORNEYaszalss Patented Feb. .6, 1 962 ice 3,020,139 ABRASIVE PRODUCT John E.Camp, Latharn, Josef C. Mueller, In, Cohoes, Frederick G. Sandholdt,North Troy, and George L. Haywood, Latharn, N.Y., assignors to NortonCompany, Troy, N.Y., a corporation of Massachusetts Filed Apr. 18, 1960,Ser. No. 22,947 19 Claims. (Cl. 51-295) The present invention relates ingeneral to polishing or abrading products and in particular to suchproducts utilizing a non-woven textile material as a backing and tomethods of making the same.

It has heretofore been proposed to utilize non-woven, felted materialsas a media for carrying abrasive grain, the resulting product findingapplication as a component of a grinding Wheel or as a polishing orscrubbing device. Examples of such products are disclosed in US. PatentNo. 2,335,902 issued to Albert L. Ball, Raymond C. Benner and Romie L.Melton. It has been found, however, that for severe abrading orpolishing operations such products find little application although theeconomics of using a relatively thick (compared to a conventional pieceof coated abrasive) backing impregnated with abrasive grain should makesuch products very desirable for many uses.

Improved products of this general type have been disclosed and claimedin the copending applications of George L. Haywood, Serial No. 782,689,and Serial No. 807,892, filed December 24, 1958. and April 21, 1959,respectively.

Still further improvement has been found possible through the use of aradically different making technique which permits positive retention ofthe loft of the nonwoven backing, accurate control of the amounts ofgrain and adhesive applied to the backing, improved adhesion betweenadjacent layers of the backing when convolute bodies thereof are formed,and most importantly, a more uniform dispersal of abrasive grainthroughout the nonwoven material.

Accordingly, it is an object of the present invention to provide a newmethod for forming non-woven, abrading or polishing materials.

Another object is to provide an abrasive article of the type referred toabove which has more uniform distribution of abrasive throughout.

Additional objects, if not specifically set forth herein, will bereadily apparent to one skilled in the art from the following detaileddescription of the invention.

In the drawings:

FIGURE 1 is a schematic illustration of the method of forming thenon-woven, abrasive-containing material of the present invention.

FIGURE 2 is an exploded, idealized view of the abrasive-containingmaterial formed as shown in FIGURE 1, illustrating the disposition ofthe fibers, the bonding adhesive and the maker adhesive and graincoatings thereon.

FIGURE 3 is a perspective view of one type of abrasive article formed inaccordance with the present invention.

Generally, the present invention resides in first treating a non-wovenweb with a bonding adhesive applied preferably in the form of a spray,resulting in a web capable of being handled without disintegration.Since, as mentioned below, the fibers forming the web are preferablynylon or other synthetic fibers, anti-wetting lubricants are generallypresent thereon. This resulting anti-wetting prop erty is generallypossessed by all such synthetic fibers and, as a result, the adhesiveapplied by the spray inherently tends to collect at the fiberintersections in the form of globules.

Accordingly, the web first formed consists of many interlaced, randomlydispersed, flexible, tough organic fibers bonded together essentiallyonly at points where they intersect and contact one another by globulesof adhesive.

It has heretofore been proposed to form such a web for use as apolishing device by using an abrasive grain-adhesive mixture to formglobules at the points of intersection of the fibers. However, toadequately bond abrasive particles to the synthetic fibers and to holdthem firmly in place during subsequent abrading operations, the adhesivemust be heat-resistant, tough and quite rigid in nature. When used tobond the fibers together, such an adhesive makes the product undesirablyharsh and stiif. Likewise, the location of the abrasive particlessubstantially only at the points of intersection of the fibers isundesirable since the abrading action is much less than is the case of amore uniform distribution of the abrasive along each fiber length.Therefore, in the present case, it is desirable that the bondingadhesive, as it is hereinafter called, be abrasive-free and that it beelastomeric in nature. The thus-formed web is. then subjected to a rollcoating operation utilizing an adhesive-abrasive slurry as the coatingmaterial. The solvent or dispersant for this second adhesive, which ishereinafter referred to as the maker adhesive and which is substantiallyharder and tougher than the bonding adhesive, is such that it has no orat most only a slight softening effect upon the first-applied bondingadhesive. As a result of these two factors, (1) the use of roll coatingand (2) the use of a different solvent or dispersant system for theharder, tougher maker adhesive, an outstanding improvement in thenon-woven abrasive product is achieved. The initial loft orthreedimensional characteristic of the web is retained since the bondingadhesive which holds the web in such three-dimensional form is notmaterially afiected by the solvent used in applying the makeradhesive-abrasive coating. Secondly, through the action of roll coating,the maker adhesive tends to deposit along the fibers in the form ofelongated strings rather than merely at the points of fiber intersectionas is the case with the usual spray application. Some of the makeradhesive surrounds and reinforces the softer, more elastic bondingadhesive at the fiber intersections as well, thus giving a verywidespread distribution of abrasive grain throughout the web.

More particularly, and referring now to FIGURE 1 of the drawings,reference numeral 19 designates a web or batt of non-woven materialformed from flexible, tough, synthetic organic filaments 11 such ascoarse nylon fibres having a diameter of up to about 300 microns. Othersynthetic fibres or filaments or mixtures thereof such as Dacron (acondensate of dimethyl terephthalate and ethylene glycol). Orlon(polyacrylonitrile) or Dynel (a copolymer of 40% acrylonitrile and 60%vinyl chloride) may be used as desired and the diameter of the fibresused may also be varied within wide limits, e.g. 25 to 300 microns. Aswill be seen from the schematic drawing of FIGURE 1, the fibres 11 areformed into desired lengths, e.g. 2 inches or so, by a suitable cutterdevice generally shown at 12 and deposited upon a moving endless support13. As the fibres 11 fall to the surface of the support 13, they may beagitated by an air blast from nozzles 14. The fibres 11 tend to fall atvarious angles to one another and to criss-cross and interlace one withthe other in a superposed, random fashion. However, it will be notedthat the tendency still is for the length direction of the fibres to liepredominately in the horizontal plane. I A web 10 of the desiredthickness is built-up--either by regulating the speed of the support 13and the rate of discharge thereon of the fibres 11 or by the use ofadditional fibre supplying stations (not shown). The fibres comprisingthe web 10 are then bonded to one another by a bonding adhesive whichmay be any of the adhesives discussed in detail below. The bondingadhesive 15 is applied by spray nozzles 16 which may be stationary orpreferably so mounted as to reciprocate back and forth across the web10. The bonded web then passes through a heating zone 17 to set or curethe adhesive 15. At this point the bonded web has 'a loft, orthree-dimensional characteristic, maintained through the location of theglobules of bonding adhesive at primarily the points of intersection ofthe fibres. It may be and is, in many instances, desirable at this pointto reverse the web and again pass it through to spray coat the oppositeside of the web with the bonding adhesive.

Experimentation has determined that if the bonding adhesive issubstantially softened by subsequent application of additional adhesive,the loft is materially reduced. Accordingly, the next step in theillustrated process, which is the application of abrasive grain to theweb is accomplished through the use of a maker adhesive having little orno softening action on the bonding adhesive. Examples of the types ofadhesive systems for use in the present method-both maker and bondingadhesives-are given below. Further, it has been determined that muchimproved adhesive distribution is achieved if the maker adhesive isapplied by a roll coater rather than through the use of the conventionalspray application; As illustrated, the bonded web 10 is passed throughroll coater 18 which consists of a pair of calender rolls 19 and 20, thelower roll 20 rotating in a bath 21 of adhesive-abrasive slurry 22. Themaker coat of adhesive and grain thus applied, thoroughly penetrates theweb 10 and tends to spread out along the fibers 11 thereof. This is moreclearly illustrated in FIGURE 2 of the drawings, hereinafter referredto. The web 10 is then passed through a heating zone 23 to set the makeradhesive. Depending upon the final form in which the web is to be used,the maker adhesive is completely or only partially dried in zone 23. Ifthe material is'to be used in flat form, e.g. as discs die-cut from theweb, the maker coat is completely dried in zone 23. If, as 'we prefer,the material is to be formed into convolute discs, the maker adhesive ispartially dried so as to remain tacky. As illustrated, the tackymaterial is then Wound into a tight convolute roll 25 as shown at 24 andsubjected to further heating in zone 26 to finally cure and dry themaker adhesive. When so treated, the adjacent convolutions are tightlybonded one to the other to essentially form a homogeneous mass. The roll25 is then cut transversely as shown at 27 to form abrasive articles 28of the type shown and described below in connection with FIGURE 3 of thedrawings.

Referring now to FIGURE 2 of the drawings, an exploded idealized view ofthe materal 10 described in connection with FIGURE 1 is shown. FIGURE 2Ashows the general relationship to one another of a group of fibres as.laid down to form the web; FIGURE 2B shows the. same group of fibresafter the spray-applied bonding adhesive has dried thereon; and FIGURE2C shows the same group of fibres after the roll-coat application of themaker adhesive-abrasive slurry. At the points of intersection 30 of thefibres 31, it will be seen from FIGURE 2B that globules 32 of thebonding adhesive have effectively encased such intersections with. aflexible bond. It will be noted that the bonding adhesive 32 tends tosettle at the fiber intersections 30 or junctions of the fibers sincethis adhesive was applied, as descirbed above, by a spray application(usually as a water dispersion). While the bonding adhesive tends tosettle substantially at the fiber intersections, occasional globuleswill adhere along the fibers as indicated at 32-. The maker adhesive 33,on the other hand, is applied by roll coating from a solvent slurry ofadhesive and abrasive grain. This adhesive 33 has better Wettingproperties and the roll coat application tends to coat themaker-adhesive along the fibers as well as at thejunctions thereof.Accordingly, as shown in FIGURE 20 the fibers 31 tend to be fairly wellcoated throughout their length with the maker adhesive 33 and abrasivegrain 34. As illustrated, the maker adhesive-abrasive grain mixture33-34 tends to form a coating over the globules 32 of the bondingadhesive as Well as coating the major portion of each fiber 31.

FIGURE 3 illustrates one form into which the abrasive material of thepresent invention may be shaped for ultimate use. The article 40 isformed from the roll 25 described in connection with FIGURE 1 by slicinga section normal to the major axis of the roll. As illustrated, theconvolutions of material are not visible which is quite common sinceproper control of tension can vary the roll density to the point where asection such as 40 appears quite homogeneous in nature. The fibers 41with the abrasive grains 42 held thereto by the maker adhesive &3provide an excellent abrading or polishing surface. This particularstructure is particularly adapted for use as a floor scrubbing pad.Other forms such as rolls or drums for industrial polishing, segmentsfor pot and pan scrubbers, etc, may be formed as desired.

The character of the present product depends upon the two-step adhesiveapplication described above with the second adhesive application beingthat which bonds the abrasive to the fibers. The second adhesive ormaker adhesive must, of necessity, be hard, tough and heat-resistant inorder to hold the abrasive grain in place on the fibers during thesubsequent use of the product in abrading or polishing. The makeradhesive therefore tends to stiffen the fibers. Accordingly, tocounteract this tendency, it is essential that the bonding adhesive,which is applied to the fibers before the maker adhesive, be flexibleenough to permit flexing and temporary dc formation of the product whilein use. For example, if the bonding adhesive used is a heat-convertibleresin such as a stiff melamine or urea-formaldehyde resin, epoxyphenolicblend, or the like, a non-resilient, friable product results. Therefore,the bonding adhesive must be relatively flexible and preferablyelastomeric in nature. It must also be relatively insoluble in thesolvent employed in dissolving the maker adhesive and preferablyresistant to alkalis. Accordingly, elastomers must be selected for theirrelative insolubility in such solvents as methyl isobutylketone, solox,cellosolve acetate and Xylene. Preferably, the bonding adhesive is basedon a nitrile rubber latex modified to impart solvent resistance. Thelatices may be modified by the use of curing agents such as zinc oxide,sodium aluminate or by the addition of resins such as phenolics,melamine or urea-formaldehyde. For example, the elastomeric bondingadhesive used in Example 1, below, was a medium butadiene acrylonitrilelatex (Hycar 1572 prepared by the B. F. Goodrich Company) having a pH of8.5 and a particle size of 1000 angstroms. This was blended with a watersoluble melamine formaldehyde resin (Resloom HP prepared by MonsantoChemical Company). Other Hycar latices which may be used include Hycar1512, 1562 and 1551. Other elastomeric materials such as natural rubber,neoprene or the like may also be used if desired.

The maker adhesives used may vary widely but generally areheat-advancing resinous adhesives based on polyurethanes, phenolics,epoxy resins or the like which adhere well to the synthetic fiber usedand which utilize a solvent system to which the bonding adhesive isresistant. Preferably, for use in floor pads or the like, the makeradhesive is also alkali-resistant and is substantially harder andtougher than the bonding adhesive.

Any of the known abrasive grains may be used in making the product ofthe present invention, e.g. silicon carbide, aluminum oxide, flint,emery, garnet and the like. Generally, the most satisfactory abrasivesare silicon carbide, garnet and aluminum oxide. The grain size maylikewise be varied Within wide limits, with grades 180, 240 and 400being the most commonly employed sizes for commercial use.

The fibers employed in the present invention are preferably syntheticfibers formed from flexible, tough, alkaliresistant, organic materialssuch as the polyamides, acrylates, polyesters, polypropylenes,polyethylene and vinylidene chloride derivatives. The preferred fiber isnylon as discussed above.

The following specific examples of products formed in accordance withthe present invention are intended to be illustrative only and thereforeonly such limitations are intended as may appear in the appended claims.

EXAMPLE I A 40 inch wide web of non-woven coarse nylon fibers-partiallydrawn producers waste ranging from 15 to 180 denier and about 1%." inlength-was prepared as described above in connection with FIGURE 1,using a conventional Rando-Webber machine and applying a spray coatingof an alkali-resistant acrylonitrile-butadiene elastomer in latex formblended with a melamine-formaldehyde resin. The Web prior to applicationof the bonding adhesive weighed 3.6 oz./ sq. yd.

Bonding adhesive Parts by weight (dry basis) Hycar 1572 latex 100Melamine formaldehyde resin 15 Stabilizer (Emulphor ON870) l Aminecatalyst AC (Monsanto) 1 /2 The wet web was then passed through aninfra-red oven to make the web tack-free. The reverse side was thensprayed with the same bonding adhesive and given a similar heattreatment. Heating was carried out on each pass for approximately 1 to 3minutes at 250-350 F. This effectively drove off the water and cured orpartially cured the bonding adhesive to the point where it wasrelatively solvent-resistant. A total weight of 1.8 oz./sq. yd. ofbonding adhesive was applied. Examination of the bonded web indicatedthat the bulk of the adhesive was deposited in the form of globules atthe junctions of the fibers.

The bonded web was then passed at a rate of feet/ minute through apadder or roll coater as described above in connection with FIGURE 1 andthe makeradhesive-abrasive slurry applied. In this case the makeradhesive was a polyester-isocyanate prepolymer blend in a solvent systemcontaining methyl isobutylketone, xylene and celiosolve acetate. Theabrasive grain (Grit No. 180, silicon carbide) was mixed with thisadhesive (Brookfield viscosity of 135 centipoises at 80 F.) in the ratioof about 150% abrasive grain based on the resin solids to form theslurry. The viscosity of the slurry was adjusted to around 950centipoises at 80 F. at the coating unit with solvent so that good fibercoverage was obtained. Too dense or viscous a slurry would tear ordistort the webas it passed through the rolls. About .097 pound ofslurry per square foot of material Was applied.

Maker adhesive-Abrasive slurry The web was then rolled into jumbo rollform and put into a curing oven. Hot air at 250 F. was blown through theroll for three hours to effect cure of the adhesive. The roll was thenready for processing into such form as might be desired for ultimateuse.

EXAMPLE 2 In some instances, particularly for fine polishing or bufiingoperations, the non-woven material formed in ac- 38.5 pounds(polyester).

cordance with the present invention is utilized without abrasive grainpresent. Such a product was formed by laying down fifteen denier 1 /2"staple nylon fibers in the manner described in Example 1 to form a loosenonwoven web weighing approximately 2.4 oz./sq. yd. This web was thenspray-bonded with an acrylonitrile-butadiene elastomer blended with amelamine-formaldehyde resin as in Example 1. The wet web was heated bypassage through an infra-red oven for 1-3 minutes at 300-350 F. (timedependent upon web speed-usually about 18 feet/minute). The reverse sideof the web was then given a similar treatment.

The bonded web was then roll coated with a phenolic resin adhesive (noabrasive) in an alcohol-Water solvent system (Brookfield viscosity of285 centipoises at F.) applied at a Web speed of 10 feet/minute and atan amount of about 7% pounds resin, on a solids basis, per sandpaperream (i.e. per 330 square feet). The phenol formaldehyde resin used hada water tolerance of 20 and a gel time at 250 F. at 5.25 seconds. Thewet web was then rolled into jumbo roll form and put into a curing ovenfor 5 hours at 250 F. The finished product was found to be quitesatisfactory as a polishing medium for tile floors after being cut intopads of the type illustrated in FIGURE 3.

EXAMPLE 3 A web of coarse nylon fibers was made as in Example 1, usingas the spray-applied bonding coat a commercial acrylonitrile-butadienelatex binder with no resin modification. The maker adhesive in this casewas an epoxy resin (Epon 815 prepared by Shell Chemical Company), andonly enough solvent (xylene) was added to the adhesive-abrasive mixtureto slightly adjust the viscosity for uniform coating. The adhesive had aBrookfield viscosity of centipoises at 88 F. before the abrasivewasadded, increasing to 1075 centipoises at 94 F. after the grain wasadded. The ratio of abrasive to resin and the amounts of slurry coatedwere as described in Example 1, The epoxy resin adhesive in the presentcase was of the low temperature curing type and curing was hereforeeffected by standing at room temperature after the web had been rolledup into jumbo roll form. This product was then mounted upon suitablebearings and used intact as a wide polishing drum.

From the above description of the present invention, it will be seenthat the spray application of a flexible, elastomeric bonding adhesivefollowed by the roll coat application of a tough, hard, resinous makeradhesive permits the retention of loft and resilience in the resultingnon-woven web while at the same time resulting in an improved dispersionof the maker adhesive over the surfaces of the synthetic fibers used informing the web. Obviously. other modifications and variations may bemade without departing from the spirit and scope of the inventiondescribed therein.

We claim:

1. An article of manufacture comprising: a three-dimensional opennon-woven web having substantial loft and a high proportion of internalvoids formed by laying down in superposed random fashion a plurality ofrelatively short flexible tough synthetic organic fibers; an elastomericbonding adhesive adhering to said fibers substantially at the points ofintersection of said fibers with one another, said adhesive bonding saidfibers one to the other so as to form a resilient web; and overlyingsaid elastorneric bonding adhesive and extending further than saidbonding adhesive along the length of said fibers, a harder, more rigidadhesive applied by roll coating without substantial softening of saidelastomeric adhesive.

2. An aricle of manufacture comprising: a three-dimensional opennon-woven web having substantial loft and a high proportion of internalvoids formed by laying down in superposed random fashion a plurality ofrelatively short flexible tough synthetic organic fibers; anelasto'meric bonding adhesive adhering to said fibers substantially atthe points of intersection of said fibers with one another, saidadhesive bonding said fibers one to the other so as to form a resilientweb; and overlying said elastomeric bonding adhesive and extendingfurther than said bonding adhesive along the length of said fibers, ahard, tough, resinous adhesive applied by roll coating withoutsubstantial softening of said elastomeric adhesive.

3. An article of manufacture comprising: a three-dimensional opennon-woven web having substantial loft and a high proportion of internalvoids formed by laying down in superposed random fashion a plurality ofrelatively short flexible tough synthetic organic fibers; an elastomericbonding adhesive adhering to said fibers substantially at the points ofintersection of said fibers with one another, said adhesive bonding saidfibers one to the other so as to form a resilient Web; and overlying aidelastomeric bonding adhesive and extending further than said bondingadhesive along the length of said fibers, a harder, more rigid adhesive,said harder, more rigid adhesive being applied by roll coating from asolvent system having relatively little softening effect upon saidelastomeric bonding adhesive.

4. An article of manufacture comprising: a three-dimensional opennon-Woven Web having substantial loft and a high proportion of internalvoids formed by laying down in superposed random fashion a plurality ofrelatively short flexible tough synthetic organic fibers; an elastomericbonding adhesive adhering to said fibers substantially at the points ofintersection of said fibers with one another, said adhesive bonding saidfibers one to the other so as to form a resilient web; and overlyingsaid elastomeric bonding adhesive and extending further than saidbonding adhesive along the length of said fibers, a hard, tough,resinous adhesive, said hard, tough, resinous adhesive being applied byroll coating from a solvent system having relatively little softeningeffect upon said elastomeric bonding adhesive.

5. An article of manufacture comprising: a three-dimensional opennon-woven Web having substantial loft and a high proportion of internalvoids formed by laying down in superposed random fashion a plurality ofrelatively short flexible tough synthetic organic fibers; an elastomericbonding adhesive adhering to said fibers substantially at the points ofintersection of said fibers with one another, said adhesive bonding saidfibers one to the other so as to form a resilient Web; and overlyingsaid elastomeric bonding adhesive and extending further than saidbonding adhesive along the length of said fibers, a harder, more rigidadhesive applied by roll coating without substantial softenin of saidelastomeric adhesive; and a plurality of abrasive grains distributedalong said fibers and bonded thereto solely by said harder, more rigidadhesive.

6. An article of manufacture comprising: a three-dimensional opennon-Woven web having substantial loft and a high proportion of internalvoids formed by laying down in superposed random fashion a plurality ofrelatively short flexible tough synthetic organic fibers; an elastomericbonding adhesive adhering to said fibers substantially at the points ofintresection of said fibers with one another, said adhesive bonding saidfibers one to the other so as to form a resilient web; and overlyingsaid elastomeric bonding adhesive and extending further than saidbonding adhesive along the length of said fibers, a hard, tough,resinous adhesive applied by roll coating without substantial softeningof said elastomeric adhesive; and a plurality of abrasive grainsdistributed along said fibers and bonded thereto solely by said hard,tough, resinous adhesive.

7. An article of manufacture comprising: a three-dimensional opennon-woven web having substantial loft and a high proportion of internalvoids formed by laying down in superposed random fashion a plurality ofrelatively short flexible tough synthetic organic fibers; an elastomericbonding adhesive adhering to said fibers substantially at the points ofintersection of said fibers with one another, said adhesive bonding saidfibers one to the other so as to form a resilient Web; and overlyingsaid elastomeric bonding adhesive and extending further than saidbonding adhesive along the length of said fibers, a harder, more rigidadhesive, said harder, more rigid adhesive being applied by roll coatingfrom a solvent system having relatively little softening effect uponsaid elastomeric bonding adhesive; and a plurality of abrasive grainsdistributed along said fibers and bonded thereto solely by said harder,more rigid adhesive.

8. An article of manufacture comprising: a three-dimensional opennon-woven web having substantial loft and a high proportion of internalvoids formed by laying down in superposed random fashion a plurality ofrelatively short flexible tough synthetic organic fibers; an elastomericbonding adhesive adhering to said fibers substantially at the points ofintersection of said fibers with one another, said adhesive bonding saidfibers one to the other so as to form a resilient web; and overlyingsaid elastomeric bonding adhesive and extending further than saidbonding adhesive along the length of said fibers, a hard, tough,resinous adhesive, said hard, tough, resinous adhesive being applied byroll coating from a solvent system having relatively little softeningeffect upon said elastomeric bonding adhesive; and a plurality ofabrasive grains distributed along said fibers and bonded thereto solelyby said hard, tough, resinous adhesive.

9. An article of manufacture comprising: a three-dimensional open nonwoven web having substantial loft and a high proportion of internalvoids formed by laying down in superposed random fashion a plurality ofrelatively short flexible tough synthetic organic fibers; an elastomericbonding adhesive adhering to said fibers substantially at the points ofintersection of said fibers with one another, said adhesive bonding saidfibers one to the other so as to form a resilient web; and overlyingsaid elastomeric bonding adhesive and extending further than saidbonding adhesive along the length of said fibers, a harder, more rigidadhesive, said harder, more rigid adhesive being applied by roll coatingfrom a solvent system having relatively little softening effect uponsaid elastomeric bonding adhesive; and a plurality of abrasive grainsdistributed along said fibers and bonded thereto solely by said harder,more rigid adhesive; said nonwoven web being tightly Wound upon itselfin convolute form while said harder, more rigid adhesive is still tackyto form a self-sustaining cylinder.

10. An article as in claim 9 wherein said cylinder is cut transverse andnormal to the long central axis thereof to form a circular pad ofnon-woven, abrasive-containing material.

11. A method for the manufacture of a non-woven polishing material whichcomprises: forming a lofty, open, three-dimensional web of flexible,tough, synthetic organic fibers by laying down in superposed randomfashion a plurality of relatively short lengths of such fibers; applyingto said fibers an elastomeric bonding adhesive, said adhesive tending toconcentrate substantially at the points of intersection of said fibersand to bond said fibers one to the other; and applying by roll coatingover said elastomeric bonding adhesive without substantially softeningthe same a harder, tougher adhesive.

12. A method for the manufacture of a non-woven polishing material whichcomprises: forming a lofty, open, three-dimensional web of flexible,tough, synthetic organic fibers by laying down in superposed randomfashion a plurality of relatively short lengths of such fibers; applyingto said fibers an elastomeric bonding adhesive, said adhesive tending toconcentrate substantially at the points of intersection of said fibersand to bond said fibers one to the other; and applying by roll coatingover said elastomeric bonding adhesive without substantially softeningthe same a harder, tougher adhesive,

said harder, tougher adhesive extending along said fiber lengths as wellas overlying said elastomeric bonding adhesive at said points ofintersection of said fibers.

13. A method for the manufacture of a non-woven polishing material whichcomprises: forming a lofty, open, three-dimensional web of flexible,tough, synthetic organic fibers by laying down in superposed randomfashion a plurality of relatively short lengths of such fibers; applyingto said fibers an elastomeric bonding adhesive, said adhesive tending toconcentrate substantially at the points of intersection of said fibersand to bond said fibers one to the other; drying said elastomericbonding adhesive to a non-tacky state; and thereafter applying by rollcoating over said dried elastomeric bonding adhesive Withoutsubstantially softening the same a harder, tougher adhesive.

14. A method for the manufacture of a non-woven polishing material whichcomprises: forming a lofty, open, three-dimensional web of flexible,tough, synthetic organic fibers by laying down in superposed randomfashion a plurality of relatively short lengths of such fibers; applyingto said fibers an elastomeric bonding adhesive, said adhesive tending toconcentrate substantially at the points of intersection of said fibersand to bond said fibers one to the other; drying said elastomericbonding adhesive to a non-tacky state; and thereafter applying by rollcoating over said dried elastomeric bonding adhesive Withoutsubstantially softening the same a harder, tougher adhesive, saidharder, tougher adhesive extending along said fiber lengths as well asoverlying said elastomeric bonding adhesive at said points ofintersection of said fibers.

15. A method for the manufacture of a non-Woven polishing material whichcomprises: forming a lofty, open, three-dimensional web of flexible,tough, synthetic organic fibers by laying down in superposed randomfashion a plurality of relatively short lengths of such fibers; applyingto said fibers an elastomeric bonding adhesive, said adhesive tending toconcentrate substantially at the points of intersection of said fibersand to bond said fibers one to the other; and applying by roll coatingover said elastomeric bonding adhesive without substantially softeningthe same a harder, tougher adhesive containing a plurality of abrasivegrains, said harder, tougher adhesive-abrasive grain mixture extendingalong said fiber lengths as well as overlying said elastomeric bondingadhesive at said points of intersection of said fibers.

16. A method for the manufacture of a non-woven polishing material whichcomprises: forming a lofty, open, three-dimensional Web of fiexible,tough, synthetic organic fibers by laying down in superposed randomfashion a plurality of relatively short lengths of such fibers; applyingto said fibers an elastomeric bonding adhesive, said adhesive tending toconcentrate substantially at the points of intersection of said fibersand to bond said fibers one to the other; drying said elastomericbonding adhesive to a non-tacky state; and thereafter applying by rollcoating over said dried elastomeric bonding adhesive withoutsubstantially softening the same a harder, tougher adhesive containing aplurality of abrasive grains, said harder, tougher adhesive-abrasivegrain mixture extending along said fiber lengths as well as overlyingsaid elastomeric bonding adhesive at said points of intersection of saidfibers.

17. A method for the manufacture of a non-woven polishing material whichcomprises: forming a lofty, open, three-dimensional Web of flexible,tough, synthetic organic fibers by laying down in superposed randomfashion a plurality of relatively short lengths of such fibers; sprayingsaid fibers of said web with an elastomeric bonding adhesive, saidadhesive tending to concentrate substantially at the points ofintersection of said fibers whereby said fibers are bonded one to theother and the loft of said web is maintained; drying said elastomericbonding adhesive to a substantially non-tacky state; and thereafterapplying by roll coating a harder, tougher adhesive containing aplurality of abrasive grains to said web Without substantial softeningof said elastormeric adhesive; said adhesive-abrasive mixture overlyingsaid elastomeric bonding adhesive and extending further than saidbonding adhesive along the lengths of said fibers.

18. A method for the manufacture of a non-woven polishing material whichcomprises: forming a lofty, open, three-dimensional web of flexible,tough, synthetic organic fibers by laying down in superposed randomfashion a plurality of relatively short lengths of such fibers; sprayingsaid fibers of said web With an elastomeric bonding adhesive, saidadhesive tending to concentrate substantially at the points ofintersection of said fibers whereby said fibers are bonded one to theother and the loft of said web is maintained; drying said elastomericbonding adhesive to a substantially non-tacky state; and thereafterapplying by roll coating a harder, tougher, adhesive containing aplurality of abrasive grains to said web without substantial softeningof said elastomeric adhesive, said adhesive-abrasive mixture overlyingsaid elastomeric bonding adhesive and extending further than saidbonding adhesive along the lengths of said fibers.

19. A method for the manufacture of a non-woven polishing material whichcomprises: forming a lofty, open, three-dimensional Web of flexible,tough, synthetic organic fibers by laying down in superposed randomfashion a plurality of relatively short lengths of such fibers; sprayingsaid fibers of said web with an elastomeric bonding adhesive, saidadhesive tending to concentrate substantially at the points ofintersection of said fibers whereby said fibers are bonded one to theother and the loft of said web is maintained; drying said elastomericbonding adhesive to a substantially non-tacky state; and thereafterapplying to said Web by roll coating from a solvent system havingrelatively little softening effect upon said elastomeric bondingadhesive a harder, tougher adhesive containing a plurality of abrasivegrains; said adhesive-abrasive mixture extending along said fiberLengths as well as overlying said elastomeric bonding adesive.

References Cited in the file of this patent UNITED STATES PATENTS2,248,064 Carlton et a1. July 8, 1941 2,335,902 Ball et a1. Dec. 7, 19432,958,593 Hoover et a1, Nov. 1, 1960 UNITED STATES PATENT OFFICECertificate Patent No. 3,020,139 Patented February 6, 1962 John E. CampJosef C. Mueller, Jr., Frederick G. Sendholdt, and George L. HaywoodApplication having been made jointly by John E. Camp, Josef C. Mueller,J r., Frederick G. Sandholdt, and George L. Ha wood, the inventors inthe patent above identified, and The Norton Company, Troy, New York, acorporation of Massachusetts, the assignee, for the issuance of a,certificate under the provisions of Title 35, Section 256 of the UnitedStates Code, deleting the names of John E. Camp, Frederick G. Sendholdt,and George L. Haywood from the patent as joint inventors, and a showingand proof of facts satisfyin the requirements of the said section havinbeen submitted, it is this 4th day of Marc 1969, certified that thenames of John E. amp, Frederick G. Sandholdt, and George L. Haywood arehereby deleted from the said patent as joint inventors with the saidJosef C. Mueller, Jr.

[SEAL] EDWIN L. REYNOLDS, First Assistant Commissioner of Patents.

1. AN ARTICLE OF MANUFACTURE COMPRISING: A THREE-DIMENSIONAL OPENNON-WOVEN WEB HAVING SUBSTANTIAL LOFT AND A HIGH PORPORTION OF INTERNALVOIDS FORMED BY LAYING